All 11- and 12-year-old boys should be routinely vaccinated against human papillomavirus (HPV), recommended a federal advisory committee yesterday. The recommendation of the Advisory Committee on Immunization Practices of the Centers for Disease Control and Prevention (CDC) follows its 2006 recommendation that all girls and young women ages 11 to 26 be vaccinated.

While vaccination against HPV has been in the news lately as a topic in a recent Republican primary debate, this recommendation is big news in part because of the scope of people affected by HPV. HPV is the most common sexually transmitted infection, according to the CDC, with about 20 million Americans currently infected, most of whom do not know that they have it. While most people with HPV don’t develop symptoms or health problems from it, it can cause genital warts, warts in the throat, and cancers of the cervix, vulva, vagina, penis, anus, and oropharynx (back of the throat including base of tongue and tonsils). Each year in the U.S., about 18,000 HPV-associated cancers affect women, and about 7,000 affect men, said Anne Schuchat, MD, the director of the CDC’s National Center for Immunization and Respiratory Diseases.

Since the committee’s 2006 recommendation, vaccination rates have remained relatively low (around a third of U.S. girls, as of 2010), in large part because the disease it prevents results from sexual activity (although not necessarily sexual intercourse). The CDC is now recommending vaccination of boys and young men in part to protect the males directly and also to potentially reduce the spread of HPV from males to females, thus protecting girls and young women. The specific age recommendation of 11 or 12 years of age is both because of a better immune response at that age and because the vaccine is most effective when given before any exposure to the virus through sexual contact, explained Dr. Schuchat.

With yesterday’s recommendation of routine vaccination of 11- and 12-year-old boys, the committee also recommended the vaccination of males ages 13 through 21 who had not already had the full course of vaccination (three shots). Vaccinations may be given to boys as young as 9 and to men between the ages of 22 and 26, although vaccination in adult males is thought to provide relatively few health benefits, given the likelihood that they will already have been exposed to HPV. As of 2009, the committee had voted to recommend that the HPV vaccine Gardasil (Cervarix is approved only for use in females) be made available to males ages 9 to 26 to prevent genital warts, but at that time it did not recommend routine vaccination. To date, only about one percent of boys have received the HPV vaccine. Following the review of new data that were not available in 2009 regarding the efficacy of the vaccine in prevention of the precursors of anal cancer (a very severe and hard to treat cancer), the committee made its recommendation in part specifically as a means of cancer prevention, said Dr. Schuchat.

Most private insurers pay for vaccines once the committee recommends them for routine use, and the health reform legislation of 2010 requires insurers that participate in health exchanges to offer vaccines that are routinely recommended by the committee. The HPV vaccine is particularly expensive, with its three doses costing pediatricians more than $300 (and patients’ families often charged hundreds more). Despite Rep. Michele Bachmann’s recent claims that HPV vaccination could cause mental retardation (a claim from which she later backed down), the vaccine has been tested in clinical trials before approval by the Food and Drug Administration, and since then, 40 million doses have been given out.